﻿// Copyright (c) Matthias Koch
//
// See the NOTICE file distributed with this work for additional information
// regarding copyright ownership.  rubicon licenses this file to you under 
// the Apache License, Version 2.0 (the "License"); you may not use this 
// file except in compliance with the License.  You may obtain a copy of the 
// License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software 
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the 
// License for the specific language governing permissions and limitations
// under the License.
// 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace XValidation
{
  /// <summary>
  /// Provides functionality to validate arguments and return value of a method.
  /// </summary>
  public class InterceptionValidator
  {
    private readonly IEnumerable<ValidationItem> _validationItems;

    public InterceptionValidator (IValidationInfoProvider infoProvider, MethodBase method)
    {
      _validationItems = infoProvider.GetValidationItems (method);
    }

    public void ValidateArguments (IValidationContext context)
    {
      Func<ValidationItem, bool> predicate = x => x.ArgumentsIndex != -1;
      Validate (predicate, context);
    }

    public void ValidateReturnValue (IValidationContext context)
    {
      Func<ValidationItem, bool> predicate = x => x.ArgumentsIndex == -1;
      Validate (predicate, context);
    }

    private void Validate (Func<ValidationItem, bool> predicate, IValidationContext context)
    {
      foreach (var item in _validationItems.Where (predicate))
      {
        foreach (var validation in item.Validations)
          validation.Validate (context.Arguments[item.ArgumentsIndex], item.ParameterName, context);
      }
    }
  }
}